An intra-operative surgical probe targeted especially for use with 511 keV photons from positron emitting radionuclides such as F- 18 is proposed. The probe uses a mercuric iodide solid state detector to enhance high energy absorption and a multi-segmented collimator to enhance spatial resolution. The multi-channel detector configuration collects data from more than one part of the probe simultaneously. Constellation has made significant gains in mercuric iodide detector technology over the past several years. Mercuric Iodide has superior stopping power due to its composition of high atomic number elements and superior energy resolution compared to scintillators. The surgical probe described herein provides the ability to operate over the energy range from 35 to 511 keV (or higher). The use of mercuric iodide provides the enabling detector technology to address high-energy surgical probes. PROPOSED COMMERCIAL APPLICATIONS: The market for surgical probes has been steadily growing over the past few years. A device that can image 511 keV would fill a market need that is currently not met. Within the United States there is a potential market of over 4,000 devices and in Europe there are over 3,000 potential devices.